Gamma rays induced variations in some cotton (Gossypium hirsutum L.) genotypes and their evaluation in the environment of Bannu.

Pure dry seeds of four cotton genotypes i.e. Gomal-93, Bt-131, Bt-121 and Bt-CIM-602 were irradiated with 10, 15, 20 and 25 kR doses of gamma irradiation from 60Co source of gamma irradiation at Nuclear Institute for Food and Agriculture (NIFA), Tarnab, Peshawar, Pakistan. The treated seed samples along with non-radiated seeds of each genotype were used as control. Field experiment was conducted in randomized complete block design (RCBD) in tri replicates in the green house of the Department of Botany, University of Science and Technology Bannu by planting the seeds during first week of June, 2012. Radiation effects on some agronomic characters like Plant height, Number of branches plant-1, number of bolls plant-1, Fibre Fineness and yield of seed cotton. The analysis of variance (ANOVA) revealed significant differences for radiation treatments, genotypes and interaction for treatments × genotypes regarding plant height, number of branches plant-1, number of bolls plant-1 and yield of seed cotton plant-1. Higher gamma rays doses adversely affected most of the parameters. Significant reduction in plant height was observed for all the genotypes under the influence of the gamma rays treatments. Increased radiation doses especially, 20, 25 kR produced adverse effect on number of branches plant-1. However in case of Bt -121, number of branches plant-1 was enhanced over the control under certain gamma rays treatments. Some of the radiation doses also produced favourable effect on the number of bolls plant-1 in varieties Gomal-93, Bt-131 and Bt -121 under 20 kR dose of radiation. The findings of the present investigations revealed that upland cotton can be successfully grown for commercial purposes in the agro environment of Bannu.